If last week's situation against the Cleveland Browns, in which the Minnesota Vikings faced a third-string quarterback, wasn't enough to get a win -- a matchup against the winless Pittsburgh Steelers could do the trick.

The Vikings (0-3) and Steelers (0-3) kickoff at dinner time in London, noon CT, on Sunday and, once again, one of these teams will come away with the season's first win.

The records are the same, the stories aren't all that different. Steelers quarterback Ben Roethlisberger has struggled behind a porous offensive line, as he's been sacked 10 times and his offense has produced just 14 points (30th) through three games. The once-vaunted Steelers defense has allowed more than 25 points per game and has not registered a takeaway.

Backup quarterback Matt Cassel will get the start, as the team announced Friday that quarterback Christian Ponder is out with a rib injury. It's a toss up if Cassel, a Pro Bowler in 2010, will improve a passing offense that is 26th in the NFL and hasn't seen a touchdown to a wide receiver yet -- something only the Jacksonville Jaguars can also say. He lost nine of his last 10 starts as quarterback of the Kansas City Chiefs before coming to Minnesota in March.

The injury bug has struck early for the Vikings. They'll be without three starters on Sunday, including Ponder and cornerback Chris Cook (groin) and safety Jamarca Sanford (hamstring). The quarterback switch has dominated headlines, but the Vikings' secondary could be an Achilles heel.

Steelers coach Mike Tomlin was the Vikings' defensive coordinator before departing for Pittsburgh in 2007. He's coached against his former team just once since leaving, beating the Vikings 27-17 in 2009 at Heinz Field.

Let's take a look at the five key matchups heading into Sunday:

For the purpleMatt Cassel vs. Steelers secondary -- The Steelers defense doesn't have a takeaway yet, but they boast the third-best passing defense in the NFL. Safeties Troy Polamalu, Ryan Clark and cornerback Ike Taylor remain some of the best in the game and have allowed just 183 passing yards per game and two touchdowns to opposing quarterbacks. After becoming a Pro Bowler with 27 touchdowns and seven interceptions in 2010, Chiefs fans had seen enough of Cassel just two seasons later when they cheered his concussion that brought backup Brady Quinn into the game. Steelers offensive coordinator Todd Haley surely had a few talking points with the team's defensive minds, as he coached Cassel for three seasons in Kansas City. Ponder has a hand in seven of the team's 10 turnovers so far. Cassel likely gives the Vikings a better chance of not being the first team to give a turnover over to the Steelers.

Opportunistic defense vs. turnover-prone Steelers -- Tied for a league-worst -9 turnover differential with the New York Giants, the Steelers almost have as many giveaways as the Vikings (10). However, Vikings defenders at each level have shown a nose for the football after generating six interceptions and four fumble recoveries in three games. That starts at the defensive line, where seven of the team's 15 pass deflections come from. The Vikings have just four sacks, due in part to quick releases by opposing quarterbacks, but tipped passes by defensive tackles Fred Evans and Kevin Williams have turned into interceptions. The Steelers had five turnovers in the 40-23 loss to the Chicago Bears on Sunday night, Roethlisberger having a hand in four of them.

OL vs. DL -- There's not a side to pick on this one, as both offensive lines have allowed 10 sacks this season. The Vikings' four sacks are disappointing, considering the star power they boast. But the Steelers have just three sacks so far, two coming against quarterback Jay Cutler last week. The Vikings dialed up the pressure last week, blitzing an uncommon 20 times for defensive coordinator Alan Williams, which led to linebacker Erin Henderson's first two sacks of the season. The Steelers are without All-Pro center Maurkice Pouncey to a torn ACL, while the Vikings offensive line has remained relatively unstable.

For the black/goldRoethlisberger vs. Vikings depleted secondary -- The Vikings will have four cornerbacks on Sunday: Josh Robinson, Xavier Rhodes, Marcus Sherels and A.J. Jefferson. With injuries to Cook and Sanford, they'll likely have to activate safety Mistral Raymond for the first time this season. Raymond opened last season as the starting safety alongside Smith, but has struggled to stay on the field with a bevy of injuries. Backup and special teams contributor Andrew Sendejo filled in for Sanford and did well in the loss to the Browns. He could start on Sunday. Even a relatively healthy Vikings secondary has allowed 315 passing yards per game (28th) to a variety of quarterbacks. Roethlisberger threw for 406 yards against the Bears last week and should have one of his easier tests of the season, barring how well the purple pass rush can get after him.

Le'Veon Bell vs. Vikings front seven -- After getting torched by one Michigan State product in Browns' quarterback Brian Hoyer, the Vikings' defense will be the first test for another former Spartan on Sunday. Rookie running back Le'Veon Bell has been battling a foot injury, but the Steelers have decided he'll make his NFL debut even though he wasn't projected to come back until after the trip to London. Running back Felix Jones has started through the first three games, but the Steelers have just 52 rushing yards per game (30th). The Vikings have allowed 114 yards per game on the ground, for a 4.4-yards per carry average, including a 34-yard run by a Browns safety on a fake punt last week.